# CVE-2011-3621: Security feature bypass in FluxBB

> Attackers can bypass security controls in FluxBB when the forum is configured behind a reverse proxy, potentially compromising user sessions or data integrity.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Jan 2020
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-q3xj-rw6r-h329

## What is CVE-2011-3621?

CVE-2011-3621 is a critical vulnerability in FluxBB, published on 22 Jan 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A reverse proxy issue exists in FluxBB before 1.4.7 when FORUM_BEHIND_REVERSE_PROXY is enabled.

## Which versions are affected by CVE-2011-3621?

It affects 1 product.


Products: Fluxbb Fluxbb.

## How do I fix CVE-2011-3621?

No fix has been published for CVE-2011-3621 yet. Limit exposure of the affected software until one is available.

## Is CVE-2011-3621 being exploited?

There is no known exploitation of CVE-2011-3621 in the wild and no public exploit code.

## Other vulnerabilities in FluxBB

- [CVE-2014-9574](https://insights.sbomify.com/CVE-2014-9574/): Path traversal in n/a (critical 9.3)
- [CVE-2020-28873](https://insights.sbomify.com/CVE-2020-28873/): Denial of service in n/a (high 7.5)
- [CVE-2014-10029](https://insights.sbomify.com/CVE-2014-10029/): SQL injection in n/a (high 7.5)
- [CVE-2021-43677](https://insights.sbomify.com/CVE-2021-43677/): Cross-site scripting in n/a (medium 6.1)
- [CVE-2014-10030](https://insights.sbomify.com/CVE-2014-10030/): Open redirect in n/a (medium 5.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-3621 and fix it if it is affected.

What it is: CVE-2011-3621 is a critical vulnerability in FluxBB, published on 22 Jan 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2011-3621 in the wild and no public exploit code.

Affected product: FluxBB. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2011-3621/ (Markdown: https://insights.sbomify.com/CVE-2011-3621/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-3621
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-3621
- OSV: https://osv.dev/vulnerability/CVE-2011-3621

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-3621/
Summaries are generated and may contain mistakes; the official description above is the record.